running

Man Kaur of India celebrates after competing in the 100-meter sprint in the 100+ age category at the World Masters Games in Auckland, New Zealand, in April 2017.
Michael Bradley/AFP/Getty Images
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Man Kaur of India celebrates after competing in the 100-meter sprint in the 100+ age category at the World Masters Games in Auckland, New Zealand, in April.
Michael Bradley/AFP/Getty Images
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New Research Suggests Why Mid-Sized Animals Are The Fastest

Researchers had participants wear the fitness trackers while walking or running on a treadmill and while riding an exercise bike to determine how well the trackers measured heart rate and energy expenditure.
Paul Sakuma/Courtesy of Stanford University School of Medicine
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In Fast-Paced China, Marathon Craze Is Off And Running (Despite A Clumsy Start)

The laces on the left are tied in a strong knot that lies horizontally. The laces on the right are tied in a knot that makes the bow lie vertically and which, according to new research, can come untied more easily.
Meredith Rizzo/NPR
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Untangling The Mystery Of Why Shoelaces Come Untied

Dr. Tonatiuh Barrientos Gutierrez, an epidemiologist in Mexico City, jogs near his home in the southern part of the capital. He says it's hard to run on the city's streets.
Meghan Dhaliwal/for NPR
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